Pristiphora leucopus ( Hellen , 1948)

Prous, Marko, Vikberg, Veli, Liston, Andrew & Kramp, Katja, 2016, North-Western Palaearctic species of the Pristiphora ruficornis group (Hymenoptera, Tenthredinidae), Journal of Hymenoptera Research 51, pp. 1-54 : 24-26

Pristiphora leucopus ( Hellen, 1948)

Nematus vitreipennis Eversmann in Kawall, 1864: 295, syn. n. Nomen oblitum. Note. Kawall (1864) published an unaltered manuscript from Eversmann’s legacy. Lectotype ♀ (DEI-GISHym30027; here designated) in ZIN, examined. Type locality: foothills of Ural mountains [In promontor. Uralensibus], Russia.

Nematus (Pristiphora) ruficornis var. leucopus Hellén, 1948: 116. Nomen protectum. No syntypes were found in MZH. Type locality: Joutseno, South-Eastern Finland, Finland and Pionerskoye [ Kuolemajärvi], Leningrad Oblast, Russia. Note. The lectotype of Nematus vitreipennis (which was the only specimen found under this name in Eversmann’s collection in ZIN) agrees well with the summer morph (completely pale metafemur) of P. leucopus ( Grearson and Liston 2012). The name Nematus vitreipennis has apparently not been used as valid since 1884 ( Brischke 1884), whereas Pristiphora leucopus has been used as the valid name for this taxon more than 25 times by more than 10 different authors since 1955 ( Lindqvist 1955). According to Article 23.9.1 ( ICZN 1999), the prevailing usage must be maintained.

Similar species.

The most similar species to P. leucopus is P. armata . Differences between these two species were extensively discussed by Grearson and Liston (2012). Whereas P. leucopus exhibits seasonal dimorphism of adults, involving leg colour and shape of the serrulae of the lancet, no such dimorphism has been observed in P. armata . Briefly, both male and female specimens which have a completely or nearly completely pale metafemur (Fig. 22 ) can be distinguished from P. armata (metafemur of which is always completely or in most part black). Other specimens, with a black or mostly black metafemur (Fig. 21 ), cannot be distinguished externally. Unfortunately, differences in lancets (Figs 54-57 ) and penis valves (Figs 83-86 ) are also small and might not always be detectable. According to Grearson and Liston (2012) the general proportions of the lamnium of P. leucopus (Fig. 54 ) are more slender than that of P. armata (Figs 56-57 ), but this does not always work, because P. leucopus can have a distinctly wider lamnium than P. armata , though serrulae are in this case somewhat weaker (Fig. 55 ). Males can perhaps be distinguished through small differences in penis valves (Figs 85-86 and Figs 9-10 in Grearson and Liston 2012), as described by Grearson and Liston (2012) (see also under P. armata ). Females with a black metafemur might also be confused with some specimens of P. confusa (if they have a com pletely smooth mesepisternum). Usually, P. leucopus (Fig. 29 ) has a uniformly dark brown pterostigma (usually basally dark brown and apically brown in P. confusa ; Fig. 28 ), but the specimens with pterostigma apically paler than basally might not be externally distinguishable from P. confusa . However, small differences in the lancets can help distinguish these species, as ctenidia in P. confusa tend to be more distinct (Figs 62-63 ).

Genetic data.

Based on COI barcode sequences, P. leucopus belongs to the same BIN cluster (BOLD:AAQ2302) as P. armata (Fig. 1 ). The nearest neighbour (BOLD:AAG3568) is 2.76% different. BOLD:AAG3568 includes P. aphantoneura , P. bifida , P. confusa , P. luteipes , P. opaca , P. pusilla , P. staudingeri , and P. subopaca . Neither does our limited nuclear data allow separation of P. leucopus from P. armata (Fig. 2 ). The single heterozygous female would have a sequence identical to the single available P. armata sequence if heterozygous sites (double peaks in chromatograms) were excluded. All the six heterozygous sites in P. leucopus include also the nucleotide found in P. armata , possibly indicating haplotype sharing between these two taxa.

Host plants.

Tilia cordata Mill. ( Kangas 1985; Grearson 2006; Grearson and Liston 2012), Tilia x vulgaris Hayne ( Grearson 2006).

Distribution and material examined.

Western Palaearctic. Specimens studied are from Austria, Finland, Germany, Great Britain, Russia, and Sweden.

Figures

Figure 1. Maximum likelihood tree of Pristiphora ruficornis group based on cytochrome oxidase subunit I (COI) sequences (1078 bp). Specimens that had at least the full barcode sequence (658 bp) were included in the analysis. Branches with multiple specimen identification labels represent identical sequences, only one of which was used in the analysis. Numbers on the nodes show approximate likelihood-ratio test (aLRT) support values and bootstrap proportions (%, BP). Support values for weakly supported branches (aLRT <0.9 and / or BP <70) are not shown. The inset shows the tree with outgroup species. The scale bar shows the number of estimated substitutions per nucleotide position. An asterisk (*) indicates the specimens that we have not studied. AUT, Austria; CAN, Canada; CHN, China; DEU, Germany; ESP, Spain; EST, Estonia; FIN, Finland; FRA, France; GBR, United Kingdom; ITA, Italy; MAR, Morocco; NOR, Norway; PRT, Portugal; SWE, Sweden; USA, United States of America. NUMTs?, possible nuclear mitochondrial pseudogenes.

Figure 2. Maximum likelihood tree of Pristiphora ruficornis group based on triose-phosphate isomerase (TPI) sequences (alignment length 842 bp). Branches with multiple specimen identification labels represent identical sequences, only one of which was used in the analysis. Numbers on the nodes show approximate likelihood-ratio test (aLRT) support values and bootstrap proportions (%, BP). Support values for weakly supported branches (aLRT <0.9 and / or BP <70) are not shown. The scale bar shows the number of estimated substitutions per nucleotide position.

Figures 18 - 36. 18 P. albitibia DEI-GISHym 31514, thorax in lateral view 19 P. luteipes DEI-GISHym 80038, thorax in lateral view 20 P. astragali holotype, thorax in lateral view 21 P. leucopus DEI-GISHym 31556, lateral 22 P. leucopus DEI-GISHym 4989, lateral 23 P. luteipes DEI-GISHym 80038, lateral 24 P. luteipes DEI-GISHym 80038, flagellum 25 P. ruficornis DEI-GISHym 31185, flagellum 26 P. armata DEI-GISHym 11092 27 P. subopaca holotype, pterostigma (arrow) 28 P. opaca holotype, pterostigma (arrow) 29 P. ruficornis DEI-GISHym 31185, pterostigma (arrow) 30 P. appendiculata DEI-GISHym 31500, claw 31 P. opaca holotype, claw 32 P. subopaca holotype, claw 33 P. armata DEI-GISHym 11554, claw 34 P. bifida DEI-GISHym 31507, claw 35 P. frigida NHRS-HEVA 000005006, flagellum with barely visible stout black setae (arrows) 36 P. pusilla DEI-GISHym 80050, flagellum with clearly visible stout black setae.

Figures 54 - 57. Lancets of Pristiphora armata subgroup. 54 P. leucopus PR. 393 VV, summer morph 55 P. leucopus PR. 467 VV reared ex larva from Tilia sp. 56 Nematus armatus Thomson syntype specimen 8 (X 112) 57 P. armata DEI-GISHym 20366.

Figures 77 - 86. Penis valves of Pristiphora ruficornis group. 77 P. appendiculata DEI-GISHym 31555 78 P. albitibia DEI-GISHym 20956 79 P. ruficornis PR. 462 VV 80 P. melanocarpa PR. 425 VV 81 P. ruficornis DEI-GISHym 19636 82 P. melanocarpa PR. 409 VV 83 P. armata PR. 465 VV 84 P. leucopus PR. 466 VV reared ex ovo from Tilia sp. 85 P. armata DEI-GISHym 80020 86 P. leucopus GBIF-GISHym 3246 (syntype of Nematus crassicornis Hartig).

Figures 3 - 17. 3 Pristiphora bifida DEI-GISHym 31507, sawsheath with large scopa (arrows) in dorsal view 4 P. appendiculata DEI-GISHym 80025, sawsheath with large scopa (arrows) in apical view 5 P. albitibia DEI-GISHym 31514, head in dorsal view showing short postocellar area (lines and arrows) 6 P. geniculata DEI-GISHym 20961, head in dorsal view showing long postocellar area (lines and arrows) 7 P. appendiculata DEI-GISHym 31500, smooth mesopostnotum (arrow) 8 P. albitibia DEI-GISHym 31516, matt mesopostnotum (arrow) 9 P. ruficornis DEI-GISHym 31185, dorsal view 10 P. subopaca DEI-GISHym 20899, dorsal view 11 P. ruficornis DEI-GISHym 31185, lateral view 12 P. subopaca DEI-GISHym 20899, lateral view 13 P. beaumonti DEI-GISHym 20766, lateral view 14 P. melanocarpa DEI-GISHym 21031, abdomen in lateral view 15 P. luteipes DEI-GISHym 18872, abdomen in lateral view 16 P. armata DEI-GISHym 11092, tergum 8 in dorsal view with apical projection (arrow) 17 P. subopaca DEI-GISHym 31560, tergum 8 in dorsal view without apical projection.

Figures 62 - 65. Lancets of Pristiphora aphantoneura subgroup. 62 P. confusa holotype 63 P. confusa PR. 544 VV reared ex larva from Salix caprea 64 P. opaca DEI-GISHym 80032 (presence of a fold is indicated by an arrow) 65 P. opaca PR. 389 VV.